stat_contour with data labels on lines

Question

I wonder how to get data labels on lines in ggplot2 for contours. Thanks

require(grDevices) # for colours

x <- seq(-4*pi, 4*pi, len = 27)
y          


        

Answer 1

This is an old question already answered, but I do a lot of contour plots and I think that there is an easier and more versatile way to do this using the package metR (https://rdrr.io/github/eliocamp/metR/f/vignettes/Visualization-tools.Rmd). This package has the function geom_label_contour() that provides an easy way to plot labels of contours. Also provides a lot of functions to plot maps.

library(ggplot2)
library(reshape2)
library(metR)
volcano3d <- melt(volcano)
colnames(volcano3d) <- c('x','y','z')

ggplot(data = volcano3d, aes(x=x,y=y,z=z)) + geom_contour() +
  geom_label_contour()

Answer 2

using directlabels package and picking solution from this

# Basic plot
v <- ggplot(volcano3d, aes(x, y, z = z))
library(directlabels)
v2 <- v + stat_contour(aes(colour = ..level..))
direct.label(v2, method="bottom.pieces")